Non-contact servo track writing apparatus and method

A servo track writing method for positioning a read/write head in a disk drive assembly wherein the read/write head is mounted on a positioning arm, the positioning arm has a through hole therein, and the positioning arm is movable by a positioning means over a media, the writing method comprising:

• detecting the edges of the through hole of the positioning arm;
• locking the positioning arm of the disk drive assembly and said tracking arm into a set geometric relationship based upon said step of detecting;
• maintaining the positioning arm and said tracking arm synchronously in said geometric relationship based upon feedback from continuing operation of said step of detecting;
• determining the position of said tracking arm and therefrom inferring the position of the read/write head inside the disk drive assembly;
• and
• directing the disk drive assembly to position and maintain the read/write head as desired for servo track writing in the media.

A servo track writing apparatus for positioning a read/write head in a disk drive assembly wherein the read/write head is mounted on a positioning arm, the positioning arm has a through hole therein, and the positioning arm is movable by a positioning means over a media, the writing apparatus comprising:

• a tracking arm located external to the disk drive assembly;
• moving means for moving said tracking arm in fixed relationship with the positioning arm;
• position determining means for determining the position of said tracking arm;
• a photodiode assembly having at least one photodiode mounted on said tracking arm;
• detection means for detecting the edges of the through hole of the positioning arm relative to the tracking arm;
• a light source;
• beam directing means for directing a light beam from said light source at the through hole in the positioning arm and then directing reflected portions of said light beam onto said photodiode assembly;
• and
• a control unit suitable to:
• determine an intensity profile of reflected portions of said light beam and further determine a first derivative from said intensity profile, to more accurately controllably permit synchronized movement of said moving means and the positioning means;
• operate said moving means and said detection means such that said tracking arm and the positioning arm attain a particular geometric relationship;
• operate said moving means and the positioning means such that said tracking arm and the positioning arm synchronously are maintained in said geometric relationship;
• operate said position determining means to measure the position of said tracking arm and therefrom infer the positions of the positioning arm and the read/write head inside the disk drive assembly;
• and
• direct the disk drive assembly to position and maintain the read/write head as desired for servo track writing in the media.

A servo track writing apparatus for positioning a read/write head in a disk drive assembly wherein the read/write head is mounted on a positioning arm, the positioning arm has a through hole therein, and the positioning arm is movable by a positioning means over a media, the writing apparatus comprising:

• a tracking arm located external to the disk drive assembly;
• moving means for moving said tracking arm in fixed relationship with the positioning arm;
• position determining means for determining the position of said tracking arm;
• a photodiode assembly having at least one photodiode mounted on said tracking arm;
• detection means for detecting the edges of the through hole of the positioning arm relative to the tracking arm;
• a light source;
• beam directing means for directing a light beam from said light source at the through hole in the positioning arm and then directing reflected portions of said light beam onto said photodiode assembly;
• and
• a control unit suitable to:
• determine an intensity profile of reflected portions of said light beam and further determine a second derivative from said intensity profile, to more accurately controllably permit synchronized movement of said moving means and the positioning means;
• operate said moving means and said detection means such that said tracking arm and the positioning arm attain a particular geometric relationship;
• operate said moving means and the positioning means such that said tracking arm and the positioning arm synchronously are maintained in said geometric relationship;
• operate said position determining means to measure the position of said tracking arm and therefrom infer the positions of the positioning arm and the read/write head inside the disk drive assembly;
• and
• direct the disk drive assembly to position and maintain the read/write head as desired for servo track writing in the media.

A servo track writing method for positioning a read/write head in a disk drive assembly wherein the read/write head is mounted on a positioning arm, the positioning arm has a through hole therein, and the positioning arm is movable by a positioning means over a media, the writing method comprising:

• detecting the edges of the through hole of the positioning arm;
• locking the positioning arm of the disk drive assembly and said tracking arm into a set geometric relationship based upon deriving a first derivative of a signal obtained in said step of detecting and locking said tracking arm in said geometric relationship based upon a peak detected in said first derivative;
• maintaining the positioning arm and said tracking arm synchronously in said geometric relationship based upon feedback from continuing operation of said step of detecting;
• determining the position of said tracking arm and therefrom inferring the position of the read/write head inside the disk drive assembly;
• and
• directing the disk drive assembly to position and maintain the read/write head as desired for servo track writing in the media.

A servo track writing method for positioning a read/write head in a disk drive assembly wherein the read/write head is mounted on a positioning arm, the positioning arm has a through hole therein, and the positioning arm is movable by a positioning means over a media, the writing method comprising:

• detecting the edges of the through hole of the positioning arm;
• locking the positioning arm of the disk drive assembly and said tracking arm into a set geometric relationship based upon deriving a second derivative of a signal obtained in said step of detecting and locking said tracking arm in said geometric relationship based upon a peak detected in said second derivative;
• maintaining the positioning arm and said tracking arm synchronously in said geometric relationship based upon feedback from continuing operation of said step of detecting;
• determining the position of said tracking arm and therefrom inferring the position of the read/write head inside the disk drive assembly;
• and
• directing the disk drive assembly to position and maintain the read/write head as desired for servo track writing in the media.